Need Help in having Itunes Tag 1 Tb of lssless Wav

..I just got a mac mini and had over 1 tb of lossless wav files that play thue itunes but i can not get the files organized thru itunes...ie artist song and album all mixed as one on itunes..triedto you us tuneup but that didnt work .. Seems I itunes can not tag these files correctily as media monkey did on my windows computer. Also i converted a few files to apple lossless but they transcribed as mp4 and also the file size was almost in half..any aideas?